New water-based coolants have recently been introduced into the automotive industry. These coolants have superior service lives and work better than older coolants with new materials currently being used in radiators. The new coolants are colored distinctly differently from the traditional bright green colored coolants previously available. Due to the formulations of the new coolant, if a system containing a new coolant is inadvertently contaminated with the old, green coolants, the useful life of the coolant will be drastically reduced. As such, any mixture of new coolant and old coolant requires that the system be completely flushed to maximize efficiency.
In order to detect leaks in coolant systems, coolant dyes are added to the system that are designed to activate when exposed to UV or high energy blue visible light. An example of such a dye is the TP-3900 engine coolant dye sold by Spectronics Corporation, Westbury, N.Y. Such dyes are green fluorescing and heavily concentrated and, thus, impart visibly green color to coolant so as not to significantly affect or change the overall color of the coolant. These dyes are also designed to produce a green fluorescence when exposed to UV or high energy blue visible light.
When conventional leak detection dyes are used with new water-based coolants, the high concentration associated with their formulation can cause the impression that the coolant has been contaminated with the older, green coolant. If service personnel mistake the new coolant for old coolant based on its dye-imparted green color, the new coolant may be unnecessary flushed. As such, time, materials and money can be wasted as good coolant is changed and systems are needlessly flushed.
Blue water-based dyes are available for coolants but they present a different problem. The automotive service industry frequently uses blue-light lamps with blue absorbing yellow glasses to excite fluorescent dyes. When used with green water-based dyes, the blue light and yellow glasses permit the green fluorescence to be readily visibly detected. A blue water-based dye, however, when exposed to the blue light will produce a blue fluoresce. Since the conventional yellow colored viewing glasses tend to absorb blue light, the blue fluorescent response exhibited by the dye will not be detected by the user. If these glasses are not used, the blue light from the lamp will overwhelm the blue fluorescent response, thus preventing a user from detecting the fluorescence.